When analyzing a vmcore resulting from a kernel failure, weoften hypothesize that "there should have a pagefault eventjust before this instruction" or similar. Sometimes it meansthat there should have a small delay between instructions thatextends a critical session and exposed a missing lock. Sincethere have been no evidence of kernel pagefault, it is quitedifficult to adopt the hypothesis.

If we can trace the kernel pagefault event, it will help narrowthe possible cause of failure and will accelerate theinvestigation a lot.